Published by Global Banking & Finance Review®
Posted on March 9, 2026
3 min readLast updated: April 1, 2026
Add as preferred source on GoogleRoche shares fell over 5% after its oral SERD giredestrant failed to show benefit when paired with Pfizer’s Ibrance as a first-line therapy in newly diagnosed ER-positive breast cancer patients. This reverses prior optimism from earlier late‑stage results showing reduced recurrence risk in treated p
FRANKFURT, March 9 (Reuters) - Roche's shares dropped more than 7% at one stage on Monday, their biggest decline in nearly a year, after the Swiss drugmaker said its promising breast cancer pill, giredestrant, failed to meaningfully help newly diagnosed patients.
Roche said the late-stage trial did not provide reliable evidence that using giredestrant in combination with Pfizer's older drug Ibrance as a first treatment slows disease progression, when compared with a standard hormonal therapy plus Ibrance regime - missing the study's goal.
By 1335 GMT, Roche shares were trading down 4.1% at 327.20 Swiss francs, their lowest level in about two months.
Giredestrant, however, could still be used as a second treatment after an earlier late-stage trial showed the oral compound cut the risk of tumour recurrence in breast cancer patients who had previously been treated. The results of that trial, last year, had boosted Roche shares.
The drug previously also succeeded as an add-on, or adjuvant, treatment in patients with a form of early-stage breast cancer.
Barclays analyst James Gordon said that the share decline was a buying opportunity as the commercial potential of add-on treatments is not fully appreciated by the market. Gordon estimates $6.5 billion in peak annual revenue for the drug in this setting.
Giredestrant belongs to a drug class known as oral selective oestrogen receptor degraders (SERD), used to fight tumours that grow in response to oestrogen - accounting for up to 80% of all breast cancer cases.
The market opportunity has also attracted AstraZeneca, which is developing rival compound camizestrant.
"This (trial) outcome aligns with our concerns that the trial was underpowered, particularly important relative to stronger trial designs like AZN's camizestrant," said Jefferies analyst Michael Leuchten, referring to AstraZeneca's study in which patients were switched to camizestrant if a mutation was detected before their disease worsened.
Roche's miss challenges the "more optimistic multi-billion-dollar narrative that had (been) rebuilt around giredestrant," he said.
Roche applied for potential U.S. Food and Drug Administration approval of the drug last month, based on data from previous studies and plans to submit data from this study in the coming weeks.
(Reporting by Ludwig Burger in Frankfurt, Puyaan Singh in Bengaluru and Bhanvi Satija in London; Editing by Linda Pasquini, Janane Venkatraman and Susan Fenton)
Roche shares dropped more than 5% after its breast cancer drug giredestrant failed to show benefits in a Phase III clinical trial.
The Phase III trial did not provide reliable evidence that giredestrant helps slow disease progression compared to standard therapy.
Roche tested giredestrant in combination with Pfizer's Ibrance against hormonal therapy plus Ibrance.
Giredestrant is an oral selective oestrogen receptor degrader (SERD) designed to fight estrogen-responsive breast cancers.
AstraZeneca is also developing a rival SERD compound called camizestrant for breast cancer treatment.
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